Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of a display screen or portion thereof withtransitional graphical user interface showing a first image in asequence, showing our new design;

FIG. 2 is a front view showing a second image thereof;

FIG. 3 is a front view showing a third image thereof;

FIG. 4 is a front view showing a fourth image thereof;

FIG. 5 is a front view showing a fifth image thereof;

FIG. 6 is a front view showing a sixth image thereof;

FIG. 7 is a front view showing a seventh image thereof; and,

FIG. 8 is a front view showing an eighth image thereof.

The outermost perimeter shown in broken lines represents display screensor portions thereof and forms no part of the claimed design.

The appearance of the transitional graphical user interface sequentiallytransitions between the images shown in FIGS. 1-8 . The process orperiod in which one image transitions to another image forms no part ofthe claimed design.

The solid black shading shown in the figures represents a contrast ofappearance.

CLAIM The ornamental design for a display screen or portion thereof withtransitional graphical user interface, as shown and described.